Scanning systems are used for a variety of image capture applications, such as web inspection and copying documents. To date, these scanning systems have utilized either Contact Image Sensor (CIS) modules or CCDs to capture the image information. In these scanning systems, CCD imagers are only a fraction of the width of the object being scanned, such as a document, because of charge transfer difficulties over large distances.
Referring to FIG. 1, a scanning system 10 with a CCD imager 12 is illustrated. A lens system 14 with or without a mirror or a mirror is positioned to focus a reduced image of the object 16 being scanned onto the CCD imager 12. An output buffer 18 is coupled to the CCD imager 12 and is used to drive the flexible cable to drive application specific integrated circuit (ASIC) 22. An input buffer 20 is also coupled to the CCD imager 12 and is used to condition signals and drive the CCD 12. The ASIC 22 is coupled to the input and output buffers and is used to interface the captured image data, digitized by Analog to Digital converter (A/D), to the host computer, networks or other peripheral devices such as printers or modems or as part of or a complete Multi-Function Peripheral (MFP) with image processing functions, motor control, light control, sheet feeder, and user interface ASIC. A desk top scanning system also contains a motor and a light source to move the imager underneath the image to be scanned. Different light sources, like florescent and Light Emitting Diode (LEDs) and different motors like stepping and synchronous motors can be used, are not shown here and are known to those in the art. Unfortunately, CCD imagers have many limitations including speed limitations due to charge transfer efficiency, large power consumption, and very limited capability to integrate other functions onto the pixel array. Additionally, in CCD imagers the pixels must be read out in a fixed sequence which does not allow for pixel information to be skipped
Referring to FIG. 2, a scanning system 30 with CIS modules 32(1)-32(5) is illustrated. The CIS modules 32(1)-32(5) are located in tight proximity to each other to construct a long contiguous array of sensors as wide as the image being captured. An optical coupler 34 is positioned to focus an image of the object 36 being scanned onto the CIS modules 32(1)-32(5). Unfortunately, since these scanning systems are as wide as the object being scanned, they are often quite large. Additionally, accurately placing together the CIS modules 32(1)-32(5) to form a complete width of the image to be scanned is an expensive process. The multiple sensors have offsets that must be corrected adding to the complexity of the system to correct offsets.